1. Field of the Invention
The present invention relates to active surface control, and more particularly to an active surface control system using a 1:3 piezoelectric composite in an active surface control system, and a method for making the same.
2. Description of the Related Art
Active surface control entails controlling the vibration in a surface by monitoring vibration in the surface with one or more sensors, and correcting this vibration with one or more actuators, typically with a negative feedback loop sending a correction signal to the actuators based upon the signal from the sensors. Usually, it is desired to cancel vibrations in the controlled surface, thereby providing a vibration-free surface. In other applications, it is desired to maintain vibration in the controlled surface at some preselected level.
Structural vibration and acoustic studies have revealed the extraordinarily complex nature of point-excited structures and of single-location monitoring. The use of large area actuators and sensors significantly reduces this complexity. Large area uniform actuators tend to couple primarily in the perpendicular direction, and tend not to excite extraneous modes or waves. Likewise, sensors that integrate response over a large area tend to extract only perpendicular wave components.
Unfortunately, construction of large area integrating sensor/actuator combinations are currently very costly. To obtain a good average response, a very large number of acceleration sensors must be used. Currently, these accelerometers must be fabricated as single units and separately wired, a costly endeavor.